The present invention relates generally to vehicle suspension systems and, in an embodiment described herein, more particularly provides a steerable suspension system having reversible caster.
It is well known to provide a steerable suspension system for rearwardly disposed sets of wheels on relatively large vehicles, such as trucks, tractors, etc. Such steerable suspension systems enable large vehicles to maneuver effectively in tight quarters, have a small turning radius, conveniently align the vehicle as desired, etc.
A typical steerable suspension system has a caster such that, as the vehicle is moving forward, the wheels "trail". In other words, the wheels tend to follow the forward motion of the vehicle, instead of deflecting laterally. This is usually accomplished by tilting to the rear the tops of longitudinal axes of king pins (typically using one king pin at each lateral end of an axle of the suspension system) about which each of the wheels rotate to steer the vehicle.
Unfortunately, when the vehicle is traveling in reverse, the caster of a typical steerable suspension system causes the wheels to tend to deflect laterally, thus preventing effective steering of the vehicle. One solution to this problem has been to lock out the steerable suspension system, thereby preventing the wheels from turning while the vehicle is traveling in reverse. However, this solution also prevents the benefits of the steerable suspension system (maneuverability, etc.) from being utilized while the vehicle is traveling in reverse.
Therefore, it can be seen that it would be quite desirable in some situations to provide a steerable suspension system which has a reversible caster, thereby permitting a vehicle to be accurately and conveniently maneuvered using the steerable suspension system while the vehicle is traveling in reverse.